§ 73.1030 Notifications concerning interference to radio astronomy,
research and receiving installations.
(a)(1) Radio astronomy and radio research installations. In order to
minimize harmful interference at the National Radio Astronomy
Observatory site located at Green, Pocahontas County, West Virginia,
and at the Naval Radio Research Observatory at Sugar Grove, Pendleton
County, West Virginia, a licensee proposing to operate a short-term
broadcast auxiliary station pursuant to § 74.24, and any applicant for
authority to construct a new broadcast station, or for authority to
make changes in the frequency, power, antenna height, or antenna
directivity of an existing station within the area bounded by 39Â°15â€² N
on the north, 78Â°30â€² W on the east, 37Â°30â€² N on the south, and 80Â°30â€² W
on the west, shall notify the Interference Office, National Radio
Astronomy Observatory, P.O. Box 2, Green Bank, West Virginia 24944.
Telephone: (304) 456-2011. The notification shall be in writing and set
forth the particulars of the proposed station, including the
geographical coordinates of the antenna, antenna height, antenna
directivity if any, proposed frequency, type of emission and power. The
notification shall be made prior to, or simultaneously with, the filing
of the application with the Commission. After receipt of such
applications, the FCC will allow a period of 20 days for comments or
objections in response to the notifications indicated. If an objection
to the proposed operation is received during the 20-day period from the
National Radio Astronomy Observatory for itself, or on behalf of the
Naval Radio Research Observatory, the FCC will consider all aspects of
the problem and take whatever action is deemed appropriate.
(2) Any applicant for a new permanent base or fixed station
authorization to be located on the islands of Puerto Rico, Desecheo,
Mona, Vieques, and Culebra, or for a modification of an existing
authorization which would change the frequency, power, antenna height,
directivity, or location of a station on these islands and would
increase the likelihood of the authorized facility causing
interference, shall notify the Interference Office, Arecibo
Observatory, HC3 Box 53995, Arecibo, Puerto Rico 00612, in writing or
electronically, of the technical parameters of the proposal. Applicants
may wish to consult interference guidelines, which will be provided by
Cornell University. Applicants who choose to transmit information
electronically should e-mail to: prcz@naic.edu.
(i) The notification to the Interference Office, Arecibo Observatory
shall be made prior to, or simultaneously with, the filing of the
application with the Commission. The notification shall state the
geographical coordinates of the antenna (NAD-83 datum), antenna height
above ground, ground elevation at the antenna, antenna directivity and
gain, proposed frequency and FCC Rule Part, type of emission, and
effective radiated power.
(ii) After receipt of such applications, the Commission will allow the
Arecibo Observatory a period of 20 days for comments or objections in
response to the notification indicated. The applicant will be required
to make reasonable efforts to resolve or mitigate any potential
interference problem with the Arecibo Observatory and to file either an
amendment to the application or a modification application, as
appropriate. The Commission shall determine whether an applicant has
satisfied its responsibility to make reasonable efforts to protect the
Observatory from interference.
(b) Radio receiving installations. Protection for Table Mountain Radio
Receiving Zone, Boulder County, Colorado: Applicants for a station
authorization to operate in the vicinity of Boulder County, Colorado
under this Part are advised to give due consideration, prior to filing
applications, to the need to protect the Table Mountain Radio Receiving
Zone from harmful interference. These are the research laboratories of
the Department of Commerce, Boulder County, Colorado. To prevent
degradation of the present ambient radio signal level at the site, the
Department of Commerce seeks to ensure that the field strengths of any
radiated signals (excluding reflected signals) received on this 1800
acre site (within the area bounded by 40Â°09â€²10â€³ N Latitude on the
north, 105Â°13â€²31â€³ W Longitude on the east, 40Â°07â€²05â€³ N Latitude on the
south, and 105Â°15â€²13â€³ W Longitude on the west) resulting from new
assignments (other than mobile stations) or from the modification of
relocation of existing facilities do not exceed the following values:
Frequency range Field strength in authorized bandwidth of service
(mV/m) Power flux density in authorized bandwidth of service
(dBW/m^2) ^1
Below 540 kHz 10 âˆ’65.8
540 to 1700 kHz 20 âˆ’59.8
1.7 to 470 MHz 10 ^2âˆ’65.8
470 to 890 MHz 30 ^2âˆ’56.2
Above 890 MHz 1 ^2âˆ’85.8
^1 Equivalent values of power flux density are calculated assuming
free space characteristic impedance of 376.7=120 ohms.
^2 Space stations shall conform to the power flux density limits at
the earth's surface specified in appropriate parts of the FCC rules,
but in no case should exceed the above levels in any 4 kHz band for all
angles of arrival.
(1) Advance consultation is recommended particularly for those
applicants who have no reliable data which indicates whether the field
strength or power flux density figures in the above table would be
exceeded by their proposed radio facilities (except mobile stations).
In such instances, the following is a suggested guide for determining
whether coordination is recommended:
(i) All stations within 2.4 km (1.5 statute miles);
(ii) Stations within 4.8 km (3 statute miles) with 50 watts or more
effective radiated power (ERP) in the primary plane polarization in the
azimuthal direction of the Table Mountain Radio Receiving Zone;
(iii) Stations within 16 km (10 statute miles) with 1 kW or more ERP in
the primary plane of polarization in the azimuthal direction of Table
Mountain Receiving Zone;
(iv) Stations within 80 km (50 statute miles) with 25 kW or more ERP in
the primary plane polarization in the azimuthal direction of Table
Mountain Receiving Zone.
(2) Applicants concerned are urged to communicate with the Radio
Frequency Management Coordinator, Department of Commerce, Research
Support Services, NOAA R/E5X2, Boulder Laboratories, Boulder, CO 80303;
telephone (303) 497-6548, in advance of filing their applications with
the Commission.
(3) The Commission will not screen applications to determine whether
advance consultation has taken place. However, applicants are advised
that such consultation can avoid objectimns from the Department of
Commerce or proceedings to modify any authorization which may be
granted which, in fact, delivers a signal at the site in excess of the
field strength specified herein.
(c) Protection for Federal Communications Commission monitoring
stations. (1) Applicants in the vicinity of a FCC monitoring station
for a radio station authorization to operate new transmitting
facilities or changed transmitting facilities which would increase the
field strength produced over the monitoring station in excess of that
previously authorized are advised to give consideration, prior to
filing applications, to the possible need to protect the FCC stations
from harmful interference. Geographical coordinates of the facilities
which require protection are listed in § 0.121(c) of the FCC rules.
Applications for stations (except mobile stations) which will produce
on any frequency a direct wave fundamental field strength of greater
than 10 mV/m in the authorized bandwidth of service (âˆ’65.8 dBW/m2 power
flux density assuming a free space characteristic impedance of 120 Ï€
ohms) at the referenced coordinates, may be examined to determine
extent of possible interference. Depending on the theoretical field
strength value and existing root-sum-square or other ambient radio
field signal levels at the indicated coordinates, a clause protecting
the monitoring station may be added to the station authorization.
(2) In the event that calculated value of expected field exceeds 10
mV/m (âˆ’65.8 dBW/m2 ) at the reference coordinates, or if there is any
question whether field strength levels might exceed the threshold
value, advance consultation with the FCC to discuss any protection
necessary should be considered. Prospective applicants may communicate
with: Chief, Compliance and Information Bureau, Federal Communications
Commission, Washington, DC 20554, Telephone (202) 632-6980.
(3) Advance consultation is suggested particularly for those applicants
who have no reliable data which indicates whether the field strength or
power flux density figure indicated would be exceeded by their proposed
radio facilities (except mobile stations). In such instances, the
following is a suggested guide for determining whether an applicant
should coordinate:
(i) All stations within 2.4 kilometers (1.5 statute miles);
(ii) Stations within 4.8 kilometers (3 statute miles) with 50 watts or
more average effective radiated power (ERP) in the primary plane of
polarization in the azimuthal direction of the Monitoring Stations.
(iii) Stations within 16 kilometers (10 statute miles) with 1 kW or
more average ERP in the primary plane of polarization in the azimuthal
direction of the Monitoring Station;
(iv) Stations within 80 kilometers (50 statute miles) with 25 kW or
more average ERP in the primary plane of polarization in the azimuthal
direction of the Monitoring Station;
(4) Advance coordination for stations operating above 1000 MHz is
recommended only where the proposed station is in the vicinity of a
monitoring station designated as a satellite monitoring facility in
§ 0.121(c) of the Commission's Rules and also meets the criteria
outlined in paragraphs (b) (2) and (3) of this section.
(5) The Commission will not screen applications to determine whether
advance consultation has taken place. However, applicants are advised
that such consultation can avoid objections from the Federal
Communications Commission or modification of any authorization which
will cause harmful interference.
[ 43 FR 32782 , July 28, 1978, as amended at 44 FR 77167 , Dec. 31, 1979;
47 FR 9221 , Mar. 4, 1982; 50 FR 39003 , Sept. 26, 1985; 52 FR 25867 ,
July 9, 1987; 52 FR 36879 , Oct. 1, 1987; 52 FR 37789 , Oct. 9, 1987; 56 FR 64872 , Dec. 12, 1991; 61 FR 8477 , Mar. 5, 1996; 62 FR 55532 , Oct.
27, 1997; 63 FR 70048 , Dec. 18, 1998; 70 FR 31373 , June 1, 2005]
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